Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uwm.edu!zaphod.mps.ohio-state.edu!samsung!xylogics!merk!alliant!linus!linus!eachus From: eachus@linus.mitre.org (Robert I. Eachus) Newsgroups: comp.sys.next Subject: Re: Mathematica Benchmarks (NeXT vs. DEC and Mac) Message-ID: Date: 4 Jan 91 15:59:17 GMT References: <1991Jan3.214940.1@linus.claremont.edu> Sender: usenet@linus.mitre.org Followup-To: comp.sys.next Organization: The Mitre Corporation, Bedford, MA Lines: 26 Nntp-Posting-Host: aries.mitre.org In-reply-to: jack@linus.claremont.edu's message of 4 Jan 91 05:49:40 GMT This sounds about right. On any memory intensive benchmark performance of the Mac II's is throttled by memory access to less than 2 MIPS (maximum memory access rate = 5 Mbytes/sec = 1.25 Million words/sec). The IIfx is also memory bandwidth limited--the memory system is much faster but so is the processor, so performance is throttled to about 5 MIPS. This is also true of the NeXT, but to a much smaller extent in the 68040 version. A 25 MHz 68030 which never has to wait for memory access can approach 8 MIPS, and some Amiga's get quite close to this when set up correctly (use SetCPU to turn on the data cache and copy the ROMs into fast memory. On a A3000 with 80ns SCRAMs this tests at about 7.7 Dhrystone 2.1 C MIPS, and shows little or no degradation on larger benchmarks). A 25 MHz 68040 can reach 25 MIPS, but as far as I know no one is yet shipping a design that does this as it can make main memory VERY expensive, and ordinary (~100 ns) memory parts don't cause as much degradation as on the 68030 due to the larger caches. -- Robert I. Eachus with STANDARD_DISCLAIMER; use STANDARD_DISCLAIMER; function MESSAGE (TEXT: in CLEVER_IDEAS) return BETTER_IDEAS is...